toolbar_tab_button_widget.hpp

// Copyright Take Vos 2020-2021.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "abstract_radio_button_widget.hpp"
#include "../GUI/draw_context.hpp"
#include "../observable.hpp"
#include "../label.hpp"
#include <memory>
#include <string>
#include <array>
#include <optional>
#include <future>
 
namespace tt {
 
template<typename T>
class toolbar_tab_button_widget final : public abstract_radio_button_widget<T> {
public:
    using super = abstract_radio_button_widget<T>;
    using value_type = super::value_type;
 
    observable<label> label;
 
    template<typename Value, typename Label = observable<tt::label>>
    toolbar_tab_button_widget(
        gui_window &window,
        std::shared_ptr<abstract_container_widget> parent,
        value_type true_value,
        Value &&value,
        Label &&label = {}) noexcept :
        abstract_radio_button_widget<T>(window, parent, std::move(true_value), std::forward<Value>(value)),
        label(std::forward<Label>(label))
    {
        this->_width_resistance = 2;
    }
 
    toolbar_tab_button_widget(gui_window &window, std::shared_ptr<widget> parent, value_type true_value) noexcept :
        toolbar_tab_button_widget(window, parent, std::move(true_value), observable<int>{}, observable<tt::label>{})
    {
    }
 
    ~toolbar_tab_button_widget() {}
 
    void init() noexcept override
    {
        _label_callback = label.subscribe([this](auto...) {
            this->_request_reconstrain = true;
        });
    }
 
    [[nodiscard]] aarect window_clipping_rectangle() const noexcept override
    {
        tt_axiom(gui_system_mutex.recurse_lock_count());
        return this->parent().window_clipping_rectangle();
    }
 
    [[nodiscard]] bool accepts_keyboard_focus(keyboard_focus_group group) const noexcept override
    {
        tt_axiom(gui_system_mutex.recurse_lock_count());
        return is_toolbar(group) && *this->enabled;
    }
 
    [[nodiscard]] bool update_constraints(hires_utc_clock::time_point display_time_point, bool need_reconstrain) noexcept override
    {
        tt_axiom(gui_system_mutex.recurse_lock_count());
 
        if (super::update_constraints(display_time_point, need_reconstrain)) {
            _label_stencil = stencil::make_unique(alignment::top_center, *label, theme::global->labelStyle);
 
            ttlet minimum_height = _label_stencil->preferred_extent().height();
            ttlet minimum_width = _label_stencil->preferred_extent().width() + 2.0f * theme::global->margin;
 
            this->_preferred_size = {
                f32x4{minimum_width, minimum_height},
                f32x4{std::numeric_limits<float>::infinity(), std::numeric_limits<float>::infinity()}};
            this->_preferred_base_line = relative_base_line{vertical_alignment::middle, -theme::global->margin};
            return true;
        } else {
            return false;
        }
    }
 
    [[nodiscard]] void update_layout(hires_utc_clock::time_point display_time_point, bool need_layout) noexcept override
    {
        tt_axiom(gui_system_mutex.recurse_lock_count());
 
        need_layout |= std::exchange(this->_request_relayout, false);
        if (need_layout) {
            // A tab button widget draws beyond its clipping rectangle.
            this->window.request_redraw(this->window_clipping_rectangle());
 
            ttlet offset = theme::global->margin + theme::global->borderWidth;
            _button_rectangle = aarect{
                this->rectangle().x(),
                this->rectangle().y() - offset,
                this->rectangle().width(),
                this->rectangle().height() + offset};
 
            _label_stencil->set_layout_parameters(this->rectangle(), this->base_line());
        }
 
        super::update_layout(display_time_point, need_layout);
    }
 
    void draw(draw_context context, hires_utc_clock::time_point display_time_point) noexcept override
    {
        tt_axiom(gui_system_mutex.recurse_lock_count());
 
        if (overlaps(context, this->window_clipping_rectangle())) {
            draw_button(context);
            draw_label(context);
            draw_focus_line(context);
        }
 
        super::draw(std::move(context), display_time_point);
    }
 
    [[nodiscard]] bool handle_event(tt::command command) noexcept override
    {
        switch (command) {
        case command::gui_toolbar_next:
            if (!this->is_last(keyboard_focus_group::toolbar)) {
                this->window.update_keyboard_target(
                    this->shared_from_this(), keyboard_focus_group::toolbar, keyboard_focus_direction::forward);
            }
            return true;
 
        case command::gui_toolbar_prev:
            if (!this->is_first(keyboard_focus_group::toolbar)) {
                this->window.update_keyboard_target(
                    this->shared_from_this(), keyboard_focus_group::toolbar, keyboard_focus_direction::backward);
            }
            return true;
 
        default:;
        }
 
        return super::handle_event(command);
    }
 
private:
    typename decltype(label)::callback_ptr_type _label_callback;
    aarect _button_rectangle;
    std::unique_ptr<stencil> _label_stencil;
 
    void draw_focus_line(draw_context const &context) noexcept
    {
        if (this->_focus && this->window.active && *this->value == this->true_value) {
            ttlet &parent_ = this->parent();
 
            // Draw the focus line over the full width of the window at the bottom
            // of the toolbar.
            auto parent_context = parent_.make_draw_context(context);
 
            // Draw the line above every other direct child of the toolbar, and between
            // the selected-tab (0.6) and unselected-tabs (0.8).
            parent_context.transform = translate3{0.0f, 0.0f, 1.7f} * parent_context.transform;
 
            parent_context.fill_color = theme::global->accentColor;
            parent_context.draw_filled_quad(
                aarect{parent_.rectangle().x(), parent_.rectangle().y(), parent_.rectangle().width(), 1.0f});
        }
    }
 
    void draw_button(draw_context context) noexcept
    {
        tt_axiom(gui_system_mutex.recurse_lock_count());
        if (this->_focus && this->window.active) {
            // The focus line will be placed at 0.7.
            context.transform = translate3{0.0f, 0.0f, 0.8f} * context.transform;
        } else {
            context.transform = translate3{0.0f, 0.0f, 0.6f} * context.transform;
        }
 
        // Override the clipping rectangle to match the toolbar rectangle exactly
        // so that the bottom border of the tab button is not drawn.
        context.clipping_rectangle = this->parent().window_rectangle();
 
        if (this->_hover || *this->value == this->true_value) {
            context.fill_color = theme::global->fillColor(this->_semantic_layer - 1);
            context.line_color = context.fill_color;
        } else {
            context.fill_color = theme::global->fillColor(this->_semantic_layer);
            context.line_color = context.fill_color;
        }
 
        if (this->_focus && this->window.active) {
            context.line_color = theme::global->accentColor;
        }
 
        context.corner_shapes = f32x4{0.0f, 0.0f, theme::global->roundingRadius, theme::global->roundingRadius};
        context.draw_box_with_border_inside(_button_rectangle);
    }
 
    void draw_label(draw_context context) noexcept
    {
        tt_axiom(gui_system_mutex.recurse_lock_count());
 
        context.transform = translate3{0.0f, 0.0f, 0.9f} * context.transform;
 
        if (*this->enabled) {
            context.line_color = theme::global->labelStyle.color;
        }
 
        _label_stencil->draw(context, true);
    }
};
 
} // namespace tt